Do Our Dogs Miss Us When We’re Gone?
10/02/2014 8:08 PM
Dogs have recently been trained to go into an MRI – fully awake – so that we can better understand how their brains work. And Yes dogs miss us when we’re gone. Dogs were trained to recognize the meaning of two hand signals, one of which was associated with a food reward. The fMRI data clearly showed responses in the caudate nucleus to the “reward” hand signal. But that was just the beginning.
The dogs have gone through a second test to examine how their brains respond to the scent of different members in their household. While in the MRI, the dogs were presented with their own scent, the scent of familiar and strange humans, and the scent of familiar and strange dogs. The results have not been published yet, but I believe it is a smoking gun for canine emotions and proof that dogs really do love their humans, even more than their fellow canines.
I have often wondered about the dogs’ perception of time. Can dogs tell the difference between 5 minutes and 5 hours? It has been found that after 2 hours, dogs greeted their owners with more intensity than after 30 minutes of being left alone. However, there was no difference between 2 and 4 hours. This suggests that dogs can tell the difference between 30 minutes and 2 hours, but beyond that it is unclear.
But what about days? Can dogs tell the difference between one day and seven? I do not know of any direct evidence for this, but we can speculate two possible mechanisms by which dogs could tell the passage of long periods of time. The first is fairly simple and based on associative memory. Through repeated pairings, a dog learns that his owner is associated with good stuff: food, play, social bonding. This is the basis of positive training. If these events are removed, it is possible that the associations will begin to decay.
The second mechanism is more sophisticated and would require that dogs have what is called “episodic memory.” This is memory for events. It was once thought that episodic memory is unique to humans, but a growing body of data suggests otherwise. In 1998, it was shown that scrub jays could remember where they had stored food based on the perishability of the items. After a long delay, the birds returned to locations with non-perishable foodstuffs. In 2005 a study showed that rats could recall objects by context and location. This “what-where-which” skill is evidence for episodic-like memories. In 2012, a further test showed rats’ ability to encode the context of where food is located. If rats have evidence of episodic memory, then it is a sure bet that dogs do as well.